‘A’ madwoman returned, a father faltered and an undercover friend emerged as an (even more) dangerous foe for the girls — and that was all just in the first half of Pretty Little Liars‘ Season 3B premiere!

The Rosewood gals were back in action Tuesday night, with no shortage of drama. Here, we’ll recap the season opener’s biggest moments, then grill executive producer Oliver Goldstick about two major developments to come out of the premiere: 1) Toby’s increasingly creepy demeanor, and 2) the seemingly nefarious Byron’s involvement in Alison’s murder.

At the start of the episode, Nutty Mona returns to Rosewood — and things immediately go to hell. At first, the ‘A’ teamer is ridiculed by her classmates, but is quickly able to morph herself into the victim with a heartstring-tugging viral video. Later, Mona opts to prove her (fake?) allegiance to the Liars by nearly offing Byron’s new-old fling Meredith — who is now the girls’ teacher and has Byron wrapped around her finger. Speaking of Byron, Aria finally begins to question her seemingly big-bad dad about his relationship with Alison, and ‘A’ taunts Aria with the knowledge of her baby secret.

Toby, meanwhile, continues to scowl at everything and everyone, while Spencer continues not to notice. (Come on, girlfriend!) Lucas spends most of the episode nursing a nasty limp, which Hanna thinks could have been from Aria’s screwdriver stab on Halloween. However, it seems more likely that Toby, in one of his recent fits of evil, ran a skateboarding Lucas off the road at the start of the episode.

Elsewhere, creepy Harold (the head of motel that long acted as home to A’s belongings) winds up with a janitor job at Rosewood High. Upon further investigation, the Liars discover that he is in possession of one of Alison’s old diaries. And here’s the kicker: It contains an entry that places Bryon in direct conflict with the ill-fated teen.

Lastly, Jason goes against his half-sister Spence’s request to steer clear of Mona, instead allowing her dress his wounds. (And no, that’s not a euphemism.)

TVLINE | I’ve asked you before and I’ll ask you again: Are you absolutely, positively certain that Toby is really that bad of a guy?
Oh yes! You got it! Very much. We’re going down a path [with Toby] and you need to know that [he] has a lot of strong motivation for wanting to take down these girls. It’s the price [they have] to pay for him taking the fall for a crime he didn’t do. This has always been present, but he’s been very good at hiding it.

TVLINE | He seemed more evil than ever in the premiere. Why is he so hell-bent on hurting the Liars now?
I think it’s Mona’s return. That’s not a coincidence. We know that Mona’s a powerful person; we know that she has no off-switch in her mind. The idea now really is that Mona’s back, Toby’s in black and Byron may be wacked! [Laughs] That’s how we started the season.

TVLINE | Speaking of Byron, we saw this week that Aria is beginning to suspect her dad of being involved with Alison — and he’s also being extremely cagey.
We’re going to discover that he had much more interaction with Alison than he ever let on. Whether he’s culpable or not for her death, we’re going to see his participation in that evening, and it really is eye-opening and shocking.

TVLINE | Could this show really make one of the girls’ parents a killer?
I know! [Laughs] You know that Hanna’s mom has already committed certain crimes — granted, in pursuit of helping her family… But our parents are not perfect; they are liars. Byron in particular has been many shades of wrong since the pilot, because of his affair and asking Aria to keep it a secret for a long time. So, this is not out of the blue. This is a person who has been deceptive, who has been a liar since the show launched, and now you’re getting to see the depths of it.

TVLINE | Isn’t it a bit of a conflict of interest for Aria to be a student in her class?
It’s up to Aria to blow that whistle. And because of what’s transpired in the premiere episode, maybe it makes more sense [for her to tough it out] to find out more about that night.

TVLINE | Lastly, talk a little about how this major baby secret will effect “Ezria” throughout the remainder of Season 3.
It will have a major impact on their relationship. It will be the biggest hurdle they’ve had to jump — even larger than having to tell her parents [about their relationship] last season. Now we’re dealing with something internal between them — and the fact is that [this secret involves] another woman in Ezra’s life. It’s not necessarily a love triangle, but there is a child. Therefore, he’s connected to someone else in a very deep way. So, this will force their relationship to grow up very quickly.